Transcriptome analysis of ozone-exposed Arabidopsis reveals that multiple signal pathways act mutually antagonistically to induce gene expression

Abstract

To analyze cellular responses to ozone, we performed a large-scale analysis of the Arabidopsis transcriptome after the initiation of 12 h of ozone exposure. By using cDNA macroarray, we identified 245 non-redundant genes that were regulated by ozone. Of these, 185 were induced and 60 were suppressed by ozone. The expression of half of the 185 induced genes was controlled by ethylene (ET) signaling, indicating that ozone-induced gene expression was mainly regulated by ET. We studied interactions between the hormonal signaling compounds ET, jasmonic acid (JA), and salicylic acid (SA) in mutants with defects in ET, JA, and SA pathways. Expression analysis revealed that many were regulated by mutual antagonism among these signal molecules. However, many cell rescue/defense genes induced by ET or JA pathways were suppressed by the SA signal, suggesting that the SA pathway acts as a strong antagonist to gene expression induced by ET or JA.